Systems and methods herein generally relate to machines having print engines such as printers and/or copier devices and, more particularly, to printer color management in image/text printing or display systems.
To meet customer demand, the commercial printing industry requires the capability of producing spot colors accurately and consistently. Spot colors can be defined as a fixed set of colors, which may be Pantone® colors, customer logo colors, colors in a customer's proprietary marked patterns, or customer defined colors in the form of an index color table. Spot colors are often used, or can be used, for large background areas, which may be the most color critical portion of a particular page. Consistent color in these areas may determine the difference between success and failure in meeting customer requirements. Customer demands for color accuracy and consistency are typically much tighter for spot colors than for colors within images.
The color gamut of a printer is a multi-dimensional space of a given volume with the axes of the space being set or defined initially by the pigments used in the colorants of the primary colors. Each set of color primaries: red, green, blue (RGB) or cyan, magenta, yellow, and black (CMYK), defines a “color space” that includes all colors that can result from any combination of these primaries. The “color space,” or “color gamut,” may be quite different for different sets of primaries. Typically, a CMYK color gamut falls inside (is smaller than) a RGB color gamut, which means that the eye can detect more colors than a printer can print. In forming multi-color output images on an image-receiving medium, each of the primary colors is transferred to the image-receiving medium in turn. The color gamut is defined by the interaction of the primary colors, and is limited by a total amount of colorant in any combination that can be effectively deposited on the image-receiving medium. In other words, it is not possible to print some colors that can be photographed or displayed on a monitor when using CMYK printing. The color gamut for a particular image forming device and an associated color rendition dictionary (CRD) by which images may be produced by the image forming device is usually stored in metadata with the image forming device. The CRD and associated set of set points programmed into the image forming device, or family of image forming devices, ensures that the color gamut produced by that image forming device covers, as broadly as possible, an available standard color spectrum. Typically then, image forming devices are delivered with a single CRD available in the image production system.
Occasionally, customers or other end-users of an individual image forming device, or family of image forming devices, may desire to produce and/or reproduce, on a recurring basis, a color or set of colors that lies outside the nominal color gamut available based on the single color gamut that comes pre-stored in the image forming device; that is, the prestored spot colors. CRDs and individual process parameter set points are not, however, user adjustable.
Some printing systems include a print engine that supports a gamut extension colorant (in addition to the usual colorants). However, a limited number (perhaps only one) of the possible gamut extension colorants can be installed in the print engine at a time. The problem for the user is to determine which colorant provides the best gamut extension for a given job. The present way of doing this is to make a proof of the job with the first colorant, swap the colorant in the engine for the next colorant, make a proof job with the second colorant, etc. The process is time consuming and tedious.